The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.
The present invention relates to ether-ketone co-polymers, particularly to hyperbranched ether-ketone co-polymers.
Dendritic macromolecules such as dendrimers and hyperbranched polymers are a new class of highly branched polymers that have distinctly different properties from their linear analogs. Both dendrimers and hyperbranched polymers have much lower solution and melt viscosities than their linear analogs of similar molecular weights. They also have a large number of chain-ends whose collective influence dictates their overall physical and/or chemical behaviors. These features are attractive in terms of processability and offering flexibility in engineering required properties for specific applications. However, there is a practical advantage that hyperbranched polymers have over dendrimers at xe2x80x9craw materialxe2x80x9d level. Although dendrimers have precisely controlled structures (designated as generations), their preparations generally involve tedious, multi-step sequences that are impractical and costly in scale-up production. Synthesis of a hyperbranched polymer, on the other hand, is a one-pot process. Large quantities of hyperbranched polymers can be easily produced from ABx (xxe2x89xa72) monomers.
Poly(ether ketones), PEK""s, are a class of well-known engineering plastics. Both linear meta- and para-PEKs have been well studied. Para-PEK generally has a very high melting point ( greater than 350xc2x0 C.), close to the degradation temperature, and limited solubility due to its semi-crystallinity. To improve the processability of para-PEK, conventional wisdom suggests the co-polymerization of the para-PEK monomer, i.e. 4-fluoro-4xe2x80x2-hydroxybenzophenone, with the corresponding meta-monomer so as to disrupt the chain packing. This should result in the reduction of the melting point and crystallinity, and improve the processability.
We have approached the preparation of less crystalline para-PEK by introducing certain degrees of branching via an AB2 monomer into the polymer chain.
Accordingly, it is an object of the present invention to provide novel ether-ketone co-polymers.
Other objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
In accordance with the present invention there are provided novel ether-ketone hyperbranched co-polymers formed by co-polymerizing 3,5-bis(4-fluorobenzoyl)phenol and 4-fluoro-4xe2x80x2-hydroxybenzophenone.
The resulting copolymer has repeating units of the formula: 
wherein n has a value of 0.25 to 0.99.